Pulsing system



Dec. l1, 1928.

E. R. LUNDlus PuLsING SYSTEM 4 Sheets-Sheet 2 k TNN xNN www ,Filed Nov. l

, NSN

2 www .n .5.366. o

` Dec. 11, 1928.

E. R. LUNDIUS PULSING SYSTEM 4 Sheets-Sheet Filed Nov. l

/n yen for [ric R und/us y Ay,

Dec.l 11, 1928. 1,695,050

E. R, LUNDIUS PULSING SYSTEM Filed Nov. 1, 1924 4 sheets-sheet 4 /n Ven for, Enf/E A und/a5 by my Patented Dec.` ll, 1928.

UNITED STATES 1,695,050 PATENT OFFICE.

ERIC R. LUNDI'US, OF RICHMOND HILL, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW`YORK, N. Y., A CRPORATION F NEW YORK.

PULsrNG SYSTEM.

Application filed November limits to properly meet service conditions and Y this adjustment must be maintainedthrough out the life of the exchange. It is the usual practice to provide testing equipment for the maintenance of apparatus adjustments and where portable test sets are required, means must be provided to make them as self-contained as is possible. This is quite difficultwhere the parts to be tested are ordinarily controlled by power driven apparatus.

It is the object of this invention to provide an improved pulsing system especially adaptable in units where it is not practical to em ploy power driven apparatus.

A :leature of. this invention relates to a pulse generating combination for a portable testing set.` i

Other features of the invention will be apparent Jtrom the following description, taken in connection with the accompanying drawing.

particularly adapted for testing machine Y switching apparatus, it will be apparent, however, from the following description that the invention has a wider utility and by slight modilication, itcould be adapted ior testing 4i) other typesot' apparatus. l

Fig. l illustrates a combined semi-mechan The testing equipment shown in Figs. 3 and'- lA nmunted in a portable container so that Vhilc the invention has been disclosed as 1, 1924. Serial No. 747,175.

the-tests may be made from a switchboard or certain frames in the apparatus room of a telephone exchange.

Power is transmitted to the apparatus of the testing circuit through jacks which are connected to the power source by patching cords and plugs. Such power connections include current supply tor 48 volts direct current, ground and alternating current.

4The apparatus connections at which symbols for the above are indicated are connected to the terminals of these jacks and thel power sources are only connected to the test circuit jacks by the patching cords when the set is in use.

Test of .sem-mechanical selector cmd 00rd- F/L'g. 1.

The test of the apparatus and circuits siiown in Fi 1 is made at a switchboard position which includes plug 190 and jacl 193. To initiate the test, the test manl inserts plug 19() into j ack 314 of the test set and associates patching cord 194Lwith jacks 193 and 312.

It the apparatus ot' the testing equipment is in its normal position, a circuit is established to light lamp 333 from grounded battery, through the filament of said lamp, lett inner normal contact of relay 357, brush 80G and its associated Contact to ground through the lower contact of key 480. When lamp docs not light, it indicates to the test man that switch 300 is not in its normal position. He thereupon operates key 345 to energize the switch magnet. This circuit may bc traced from grounded battery through the winding and contact ot magnet 307, brush 302 and its associated contacts in positions 2 to 13 or 15 to 22, to ground, through the up` pcrmost contact ot key 345. The switch brush assembly now rotates under the control of its seltlinterrupting contact until brush 302 progresses beyond terminal 22. Assuming that lamp 833 has lighted, indicating that the switch is in its normal position, key 346 is now operated to advance the switch from position 1 to position 2. The energizing circuit for the switch magnet 307. may be traced from grounded battery, through the winding ot said magnet, contact of key 3&2, contact of key 346 to ground through the contact of key 348. The construction ot' the switch is such that the stepping pawl, advanced over a tooth of the stepping ratchet wheel upon the energization et tlieimaguet. vUpon Vthe re lease ot key 3110, the release of said niagnet advances the brush assembly to terminal 2.

In position 2 of switch 800 a circuit is established to light progress lainp 38,2 from grounded battery, through the tilanient ot said lainp, brush 300`and its associated contact to ground through the lower contact of Vley 480. A continuity-test now Vinade of the coiuluctors and apparatus associated with the tip and ring contacts ot plug 190. VThis circuitn'iay be traced troni grounded battery, through the winding otrelay 113, left lower winding oit reueating coil 114, lower Vcontact of relay 115, coi'iductor 116, ring con- 'iug oit `iacl 31a,

ductor ot plug 190, ring s1 left/'inner noiairalY contact 'et relay 35S, lelt outer normal contact et re y 353, brush 305 and its associated contact, wii'idiug ot relay 350, 'brush 80% and its associated Contact, right outer no'rnial Contact oit relay 353, right norinal contact of relay 358, tip spring Aoi" 'jacl 551--, tip ot plug 190, conductor 117, up-

per norinal contact of relay 1.15, lett upper 1 winding ot repeating coil 114 to ground. llelar'np 320 to grounded battery.

lays 113 and 350 are operated in the circuit traced. The operation of relay y350 establishes a circuit tolight lain p B20 Vtroni ground tl'irough the cont et of relay 350, iilainent of The illuniination oit lainp 320 indicates to the test inan that a continuous circuit is established. The operation oit relay 118` not ellective at this tin'ie. Upon the illumination oi' lainp 320 `key 346 is again Aoperated and released to advance switch 300 to terminal 3. Magnet 307 is energized and deenergized previously described. Y

In position 3 of the switch, progress lanip 331 is lighted troni grounded batter through the lainp lilainent brush 300 and its associated contact toY ground through the lower contact o'r key 480. A non-operate test ol? relay 150 is now inude by establishing a high resistance circuit through its winding. Tliisniay betraced lroiu grounded battery, through the winding el' relay 150, conductor 101., sleeve of plug 190, sleeve o'lfjack 3141, leiit outer norinal contact of relay 357,

resistances 381 and 882 to ground through :v y i c l 1 brush o0oanu its associated contact. Relay 150 should not operate Vwhen this test is applied. The operation of this relay would indicate that its spring asseinblj-,i is not in adjustinent. tion ol'other relays in thedistrict selector which would, in turn, rotate the' sequence switch and illuiui; e lainp 112 in the inannei' describeiif, in Patent No. 1,531,080,` :sued lilarch 24, 1925 to lNilliani L. lodge. Assuming that relay 150 remains in a non-operated position, vkey 340 is again operated and released to 4advance switch'300 to position 4.

1n position't 'a circuit is established to liglht lainp 330 which circuit may be traced in a i 1 similar manner to that established for light- Ythrough thefwindingjof nagnet 190, left This will be shown by the opera-l ing lan'ip 331. A circuit is further kestablished to operate relay 357 'troni grounded battery through its winding to ground through brush'803 and its associated Contact. An operate test ot relay 150 is now inade by associating the proper Value of resistance in A circuit'with its winding. This circuit inay be traced from grounded battery, through the Winding ot relay 150, conductor 101,

`sleeve of plug 190, sleeve of jack 31d, lett outer contact ot relay 357, resistance 382 to ground through the right outer contact of relay U57. Resistance 382 is et such `VValue that it relay 150 is in proper adjustment the current through its winding is just enough `to iactuate its associated armatures.V Assuming that relay 150 operates over the circuit traced acircuit is established to voperate relay 103 ,trein grounded battery,through theV lett contacts .of key 102, winding of said relay, llower contact ol' relay 150 to ground, through the right lower contact of cani 104. The operation oit relay 103 establishescir- Vcuits to operaterelays 105, 106 and 107 from Ved ytro-ni grounded battery, `through its lilamcnt', left lower contact of cani 111 to ground through the right inner Contact ot relay 105.

This is an indication that re ay 105 oiierated.y

in responseto -the operation relays 150 and 103. rThe operation oit relay 107 est-ablishes a circuit to lenergize sequence switch icc magnet 120 and thus rotates thesequence ion 1 `tol position f. ed 'fi-oni 'rounded battery,

switch 'troni posir circuit maybe tri' lower contact of cana 119 to ground throne the right contact of relay V107. .lt will ce noted that upon the operation of relay 103v a circuit was established to energize the winding of. relay, 1`15,.this energizing path, however, is shunted by a ground at cani 1041l until the `seque-nce switch rotates out of position This llt)

iis f 1.1/1, At this tiine relay 115 operates from this enei.izing circuit which inay be traced frein ground through its winding. lett inner contact and wiudingof relay 103 to ground ed battery at heyY 102. It will further he noted that the circuit traced. tor the operation of relay establishes a locking circuit for relay 1.03 so that it remains operated after therotation of the sequence switch out of .position 1, and the continued operation of relay 103 maintains relays 105, 100 and 107 in their operated positions. This coii'ipletes the voperate test of relay (1.50 and key 346 is again operated and released to advance the brush members of switch 300 to position 5.- v Progress lamp 329 is lighted in this posiin its operated position.V The circuit through contacts of relay 115` is shown yschematically as extending through the operator-s telephone circuit 195 including receiver 196. For this test alternating.current conducted through a retardation coilbridge, so that a tone is carried through the operators telephone apparatus to receiver 196. This circuit may be traced from the alternatingr current source 390, condenser 391, retardation coil 370, brush 305 and its associated contact, lett outer normal contact of relay 353, left inner normal contact of relay 358, ring spring of jack 314, ring of plug 190, `conductor 116, lower alternate contact of relay 115, apparatus of telephone circuit 195 and rec-civerl96, upper alternate spring of'relay 115, conductor 117, tip of plug 190, tip spring of liack 314, right normal contact of relay 353, right outer normal contact of relay 353, brush 304 and its associated contact, condenser 391 and alternating source 390. The bridge Vcircuit traced allows sufficient alternating current tone to be carried through the circuit apparatus and receiver to be audible tothe test man.

The routeV code and start keys in the switchboard that are required for driving the district circuit (Fig. 1) to the test line are now operated and the district selectorsequence switch advances to the selection beyond position No. in the manner described in the aforementioned patent to William L. Dodge. In this position of the district selector sequence switch a circuit is established through the winding of relay `.355 over a loop extended through the sender circuit. i This circuit may be traced from grounded battery,

1 through the winding of relay 355, right inner normal contact of relay 351, tip spring of jack 312, tip'of plug 191, tip conductor of patching cord 194,tip of plug 192,tip spring ofjack 193, terminal 149 of the test line, brush 152, right upper and left lower contacts of cani 125, left outer contact of relay 174, thence over a loop circuit through the sender returning through the lower contact of cam 160, brush 153, terminal 151, ring spring of jack 193, ring of plu g 192, ring conductor of patching cord 194, ring of plug 191, ringspring of ackj312, lett normal contact of relay 351 to ground through brush 303 and its associated contact. Relay 355 operates in the circuit traced and establishes an obvious circuit to operate relay 356.

`The operation of relay 356 vestablishes a circuit to operate relay 3i 8 from ground through its right outer contact, Winding of relay 358 to grounded battery. The operation o't relay 356 further establishes a circuit to ener.- gize switch magnet 307, from grounded battery, through the wind ing oi' said switch magnet, right inner contact of relay 356 to ground through brush 301 and its associated contact. Magnet 307 is now maintained in an energized position and the brush members are not propelled to the next position until the release of relay 356. The circuit through the sender apparatus as previously described tor the Voperation oit relay 355 operates the apparatus in the sender, which operation energizes scquence switch magnet 120 in the district selector switch. This encrgiaing circuit tor switch magnet 120 extendstrom ground in the sender through the right lower contactot cam 119, through the winding of the sequen ce switch magnet to grounded battery. The district sequence switch now rotates to position 14. The rotation of the sequence switch opens the energizing circuit for relay 356`to cause its release, which in turn opens the energizing circuit 'tor switchmagnet 307 to advance the brush members of switch 300 to position 6. A locking circuit is established for relay 358 and it therefore does not release upon the release of relay 356. `This locking circuit may be traced from grounded battery,

i, through the Winding and left outer contact ot relay 353, thelet't normal contact of relay 359., upper contacts of key 345, sleeve of jack 312, sleeve ot plug 191, sleeve conductor of patch.- ing cord 194,'sleeve of plug 192, sleeve 'of 'jack 193, terminal 146, brush 144, brush 155, coinmutator 154 to f rroundv through the left upper and lower contacts of cam. 141. A circuit is now established to operate relay 113, through the contacts of relay 358. This circuit may be traced from grounded battery, through the Winding ot relay 113, left lower winding of repeating coil 114, lower continuity contacts of relay 115, upper' contacts ot relay 115, conductor 117, tip of plug 190, tip spring ot jack 31.4, right contact of relay 358, lett inner contact ot relay 365, retardation coil 370, lower contacts ot key 344, left outer normal contact of relay 365,' left inner contacts ot relay 353, ring spring of ack 314, ring of plug 19t), conductor 116, lower contact of relay 115 upper continuity contact ot relay 115, lett upper winding of repeating coil 114 to grourul. Relay 113 operates and lamp 112 is lighted trom groundedbattery through its filament, contact ot relay 113 to ground through the left contact and winding ot relay 167. A circuit is established to operate relayr 126 Viu position 14 of the district selector sequence switch from grounded. battery through the Winding of said'relay, right outer contact of relay 105 to ground through the flett lower and right upper contact of cam 143. i

In position 6 of switch 390 a. `circuit is established to light progress lamp 3a( si 'iilar to that previously des. 'ibcd 'for other prog'- ress lamps. A further circuit is established to operate relay 35.1 from grounded battery,

ytion of relay 351 establishes a low resistance circuit for a saturating operate test oflpolarized relay 163. This circuit may be traced from ground through the left winding of relay 361-, brush 305 and its associated. contact, left outer normal contact of relay 353, left contact of relay 351, ring spring of jack 312, vring oi plug 191, patching cord 1911 and plug 192, ring spring of iaclr 193, terminal 151, brush 15.3, upper contact ot cam 160,lower Contact of relay lett contact of ley192, lower contact of relay 1.26, right lower winding el repeating coil 114., lower contact of carn 165, win oit'relay 163, upper contact of vcani 1611, right upper y finding of repeating v coil 114-., upper contact of rclay126, right con- Vtip spring oit jaclr 193, ti poli plug 192, patch-A i 31.2, right inner contact ot relay tact of hey 192, upper contact of relay126, Contact oi cam 16.6, brush 152, terminal 149,

ing' cord 1941 and plug` 191, tip spring of jack 1 351, right outer normal contact ot relay 353, brush 304 and its associated contact, right outer normal Contact orelay Z154-, resistance 1179 to: grounded battery. Relay 3641 operates to establish a circuit from ground through its contact, lilament of lamp 32()` to grounded battery. The

that a circuit has been established through relay 163 and that false grounds are not connected to any part of the circuit traced. Re-

lay 163 also operates in the circuit traced, and establishes an. operating circuit for relayy 136 'from grounded battery, through the winding of said relay, right' normal contacts of relay y168I vto ground through the contact oli relay 163. Relay 136 locks over its inner contact to ground at the left contact ol cam 1941. Key 346 is again operated and released at this time to advance switch 309 to position 7.

ln position 7 of switch 300 progress lamp 32'? is `lighted over a similar circuit to that traced for previous progress lamps. lt will he noted that the operating circuit lor relay 163 is opened upon the advance ott switch 300 to position 7. Upon the release' of relay 163, a circuit is established to operate .relay 168 troni ground, through the Contacto` relay 163, right Contact oli relay 136, right lower and left uppeiiicontacfts ol" cani 1.69, winding oft relay 163 togrounded battery. In this position ol switch 300, relay 361 is associated in circuit with relay 163 over the tip and ring conductors of the district selector circuit. Therefore, it battery potential is connected to the district apparatus or the tip or ring.

conductors, relay 364 will operate. Battery should not be connected to said conductors or apparatus this time. The circuit or this test may be traced from ground through the left winding of relay 364, brush 395 'and its associated contact, lett outer normar conn tact of relay .35.3, let contact ot relay 351, ring spring oi jack 312, ring oit plug 191,

patching cord 1941, and plug 1.92, ring springV ofijacl; 19.3, terminal 351, brush 153, upper contactot learn 160., .lower Contact of relay 126, left contacto'f key 192, lower contact of'V relay 12.6, right lower winding ot repeating.

coil 1141, lower contact kof cam1615., windingV of relay 163, ripper contact of cani 164,'right upper winding of repeating coil 1111, upper contact of relay 126, right contact of lrey 192, upper VContact of relay 126, lower conta-ct of ca1n166, brush 152, terminal 149, tip spring oit jack 193, tip of' plug 192, patching cord 194, plug 191,'tipspring ot jack 312, and thence to anropen-ended circuit at brush Since no battery is supplied in this circuit relay 3641 does not operate, unless aulty'pd tential is associated with the apparatus or conductors of the district selector. If this Vfaulty battery potential should .be associated with the apparatus or conductors of the sclcctor circuit, relay 364 operates and establishes'a circuit to light lamp 329 as prf-iviously traced. This indicates to the test man that trouble is encountered in the selector circuit.V Assuming that no trouble is encountered Vkey 316V is operated andv released to advance switch 390. to position 8.' p

In position 8 of switch 300 a circuit is established to light progress lamp 326 over a circuit similar to that previously traced for other progress lamps. A non-operate test is new appliedto relay 163, through resistances of vtheproper value to allow sufficient current to liow through the circuit established to operate relay'163 it it should beouto't adjustinent. This circuit may be traced 'from ground through the lett winding of relay 364,

vbrush 304-. and its associated contact,ri,f ;ht

light lamp 320 as previously traced.' ltr-elay 163 remains in a non-operated position, lamp 110 in the district selector and cord circuit does not operate. It, however, relay 163 operates when the non-operate test is applied, a circuit is established from ground, through its contact, rightrcontact of Vrelay 168, through the filament oflamp 110 to grounded battery. The illumination of Vlamp 110` indicates to the test man that relay 163 has operated falsely and is, therefore, not

in proper adjustment, Key '346 is operated and released at this time to Vadvance'switch 300 to position 9. j i A s In position 9 olf switch 309 a circuit iis fdl

tablished to light progress lamp 325. A fur-v ther circuit is established to operate relay 352 from grounded battery, through its 'winding to ground, through brush 303 and its associated contact. The operation ot relay 352 establishes a circuit et the proper resistance Value to operate relay 163. This resistance' winding oll relay 163 as `previously traced,

returning over thev tip of plug 191, tip spring oit jack 312, right inner contact of relay 351 to ground through the right inner contact of relay 352. The operation of relay 163 establishes a circuit to light lamp 110 as previously traced. This indicates to the test man that. relay 163 has operated. Key 346 is now operated and released to advance the switch 300 to position 10.

A circuit is established in this position of the switch to light progress lamp 324 from groiuuled battery, through the lamp filament, left lower contact of key 342, right normal Contact of relay 368, brush 306 and its associated contact to ground through the lower contact ot key 480. lllashing key 192 is tested in this position. The operation of key 192 establishesv `an energizing circuit ior relay 368. This circuit may Lbe traced from grounded battery through resistance 194, i ht contact of key 192, upper contact ot rc y 126 contact of cam 166, brush 152, terminal 149, tip spring ot jack 193, tip of plug 192, tip conductor oi' patching cord 194,- tip ot plug 191, tip spring of jack 312, right inner contact ot relay 351, which has remained in an operated position, right outer normal contact ot relay 353, brush 304 and its ass-:ociatcd contact, winding of relay 368, brush 305 and its associated Contact, .left outer normal contact ot relay 353, left contact o't relay 351, ring spring of jack 312, ring of plug 191, ring conductor of patching cord 194, ring ot plug 192, ring spring of jack 193, terminal 151, brush 153, of cam 160, lower ccntact of relay 126, lett ccntact of key 192, resistance 193 to ground. Key 192 may` now be operated and released a ninnhcr ot times to flash lamp 324. Each operation ot key 192 establishes t-he operating circuit for relay 368, and the release of key 192 opens this circuit to cause the release of said relay. Key 346 is again operated to advance switch 300 toV position 11.

The progress lamp 323 corresponding to position 11 ot switch 300 is lighted to indicate the position ot the switch to the test man. This circuit may be traced troni grounded Vbattery through the lilanient of lamp 323,

upper contact.

brush 306 and its associated contact to ground through the lower contact of key 430.` A further circuit is established to operate relay 365 from grounded battery,ithrough its winding to ground through brush 303 and its associated contact. The operation of relay 365 establishes a loop circuit over which relay 113 is operated. This circuit may be traced from grounded battery through the winding of relay 113, left lower winding oi' repeating coil 114, lower and upper contacts of relay 115, conductor 117, tip of plug 190, tip spring of jack 314, right contactoi" relay 358, lett inner contact ot' relay 365, upper normal contact of key 344, low resistance 372, lett outer contact ot' relay 365, lett inner contact of relay 358, ring spring of ack 314, ring ot plug 190, conductor 116, lower and upper contacts of relay 115, le't't upper winding of repeating coil 114 to ground. The operation of relay 113 establishes a circuit to light lamp 112 as previously traced through the lett winding of relay 107'. Key 344 is now operated to add other resistances in the testing bridge, which resistances are suliiciently high to cause the release of relay 113. i The high resistance bridge circuit may now be traced fromgrounded battery, through the winding of relay 113 to the tip spring of ack 314 as previously described, thence through the right contact ot relay 358,1ett inner contact ot relay 365, resistances 374, 373 and 372, left outer contact of relay 365,. lett inner contact ot relay 358, ring spring ot jack 314 and thence to ground through the lett upper winding ot repeating coil 114. Key 344 may be repeatedly operated and released which should cause relay 113 to operate and release and v flash lamp. 112. This is an indication'to the test man that relay 113 is in proper adjust- Y ment.

Since no tests are made in positions 12 and 13 of switch 300, key 346 is operated andreleased a sulhcient number of times to advance v the brush assembly to position 14. This coinpletes the test ot the cord and district circuits shown in Fig. 1 and the apparatus also shown in F ig. 1 is restored to normal by the removal of the plugs o` the testing jacks.

Test of local semi-mechanical district selector-Figure Q.

v,those shown on switch 300 and that brush members 401, 402 and 403 are opposite in relation to the switch positions oit brush meinbers 404, 405 and 406, so that during the time that brush members 404, 405 and 406 are associated with position terminals, brush meml Ui) Cir To initiate the test o-the apparatus and circuits of the selector switch (Fig. 2)-, plug 228 is inserted in jack 229, plug 226 into jack 227, plug 224 into jack 892 and plug 225 into jack 316. Jacks 229 and 227 are located 4on a frame in the apparatus rooni adjacent to the apparatus shown in Fig. 2. The portable box is placed near the jacks so that patching cords'250 and 251 may connect the portable testing boX to the ltraine jacks 229 and 227 andthe test man may Wat-ch the functioning of the apparatus during the test. Key 842 is now actuated by the test man tojestafblish` an operating circuit tor relay 858'.` This-eircuit may be traced roin grounded battery, through resistance 885, winding-oi relay'3535, right upper Contact of key 842 to ground through brush 3013'and its associated Contact. Lamp 478 is lig ited to indicate that switch 400 is resting in its norinal position. This circuit 'may be traced troni grounded battery through the l'a'rnp filament, brush 406 land its associated contact', `brush 306 and its associated Contact to ground through the lower cont-actief key 480. Certain ones ot the keys in each of( the thousands, tens and u'nitskey sets are now operated t'o control the selection of the test line `by the district selectorA (Fig. These Ilreys are know'nxas recording keys and are mechanically locked. `The contacts 481', 482 and 483'are closed when any one `key in each strip is '(ipf-Jrated;v Key 346 is now operated to establi'sl'i a circuit for sta-rt relay 457. Thiscircuit inay be traced fr'oin ground-- ed battery, through the winding of relay 457,

contacts 488, 482 and 481, upper contact 'of key 346, lett inner contact ofrelay 853 to Y ground through brush 308- and its associated contact. The operation of relay 457 estab-V l-ishesa locking circuit for itseltv through its left innerconta'ctto the ground as :previously traced for its-operating circuit. Y

The operationot relay 457 liiurther associates relay 4i58-and resistance 472 with the tip and ring comluctors oi" the @district selector (Fig-2) to start theoperation oi the district selector circuit. This circuit inay be traced from grounded battery through ,the winding of relay 228, lett contacts oicanill, leiI t outer norinal contact of relay 22, lett contacts or cano 210, tip spring o'it Jack 229, `tip ot plug 2128,

patching cord 250 and plug 224, tip'spring' of jack 892, -letouter contact ot relay 358, brush 305 and its `associated contact in position 174, lelit'out'er contact' ot relay 457, res iran-co4? 2, winding of relay 458, rig outer Contact of relay 457, brush 804-, and'its ociated contact, right outer contact of relay, ot jack 892, ring oit n ig 20 ,j tching cord 250-andfplug'228, rin springer {gat-l; 229, flott lower andright up ground through tlV richt oi'itcr Contact ot' relay Relays 228 and operate inthe circuit traced. i Resistance 472 in conjunction ontacts ci cain 215 to.

with the resistance of relay 458 is oi' such value that anoperating test is made atthis tinieV upon relay 223. The operation of relay 458 establishes an operati-ng circuit for relay 460 v troni grounded battery, through its winding, right outer normal contact oit relay 459, contact ,oii relay 458brush 404 and its associated contact to Vground through the right inner normal contact of relay 468. The contactsof relay 460 do not establish effective circuits at this time. i

The operationof relay 223 establishes an en*- ergizing circuit for relay 221 which niay be traced troni grounded battery, through the cain 2118 to groundfthrough the contact otrelay228. 'Phe operation 0i' relay 224 establishes vanl energizing circuit for the sequence switch-magnet 200, which may betraced trono grounded battery, through its winding, left upper contact `of cani 202 to ground through the right contact ot relay 221'. The sequence switch now rotates troni fposition 1 to position 2. ln this positionot the sequence switch a circuit is established to operate relay 222 which may be traced troni ground through the upper contacts o-i' cani.216,vwindingfofrelay 222 to grounded battery, throughthe winding` and contact of the sender selector magnet 220. The resist-ance of relay 222 is ot a high ..falue and magnet does not 7obtain suiiici'ent current to operate. The

lergizingcirciiit for the magnet 407 associated with switch 400. This circuit may be traced froinfgrounded battery, through the winding y oitl magnet V407 and its associated sell-interrupting contact, left contact of relay 459, right outer contact ofrelay 460, brush 404 and its associated contact to ground ythrough the right inner contact of relay 468. The operation and release ofinagnet 407 under the4 control o-f its sell:` -interrupting contact rotatesV brushes 404', 405 andv 406 into association with the second position terminals. ln this posirigh-t winding of relay 221, lower contact ot' .80 v

tion of the switch a circuit is `established to Y energize switch magnet 807 to rotate its brush rneinberslroin position 14 toposition v105. This circuit may be traced troniv grounded 4batt ry, through the w-indin and associated contact ot' niagnet 307,1iglit inner contacts of relay switch 300, lamp 478 is extinguished andlainp cuits to send the lirst pulse to a sender which has been selected by theselector switch shown in Fig. 2. This sender isof the local sender type fully described `in the Patent No. 1,531,080, issued March 24,1925 to lillia-ni L. Dodge. f y

Let it be assumed that the test man operates keys 416, 424 and 433 to establish circuit paths for pulses of various character to set the sender-,apparatus in a manner to direct the selector switch (Fig. 2) to' the test line indicated by terminals 236, 237 and 238. The initiall pulse is transmitted over a loop eX- tending tothe sender of the loop the tip conductor being closed upon the operation of relay 462 from grounded battery through high resistance 471, right inner contact of relay 454, left Contact` of key 416, left contact of relay 450, leftinnerV contact of relay 462, left inner contact of relay 466, left outer contact ofrelay 457', brush"305, and its associated contact in position 15, left outer contact of relay 353, tip' spring of jack 392, tip of plug 224, patching cord 250 and plug 228, tip

spring of jack 229, conductor 252, left lower and upper contacts of cam 210, left outer contactof relay 222, left upper contact of cam 208, brush 225, and thence to the sender register apparatus as described in the previously mentioned patent to William L. Dodge. Si-V brush 227 and thence to the sender registerV apparatus as described in the previously mentioned patent to William L. Dodge.

A battery pulse through a high resistance is effective upon the sender register apparatus as a light negative pulse, battery through a low resistance as a heavy negative `pulse and ground as a positive pulse.

The operation of relay 462 further establishes a circuit to operate relay 461 from grounded battery, through the Winding of `right Contact of relay 463, brush 406 i traced from grounded battery, through thel winding vand associated contact of magnet 407, lett contact of relay 461, brush 404 and its associated contact to ground through the right inner contact of relay 468. It should be noted that relay 461 is a slow operating relay in order to allo7 suiicient time for the first pulse to be transmitted to the sender bevfore switch 400 advances from position 2 to position 3, and further that relay 467 is slow to release in order to allow further time for pulsing before establishing circuits to energize the next pulse relay 463. rlhe rotation of switch 400 from position 2 to position 3 opens the energizing circuit for relays 461 and 462 to cause their release. The release of relay 461 opens the energizing circuit of relay 467. The release of relay 467 establishes a circuit to rotate the switch from position 3 to position 4. This circuit maybe traced from grounded battery through the winding of magnet 407 and contact associated therewith, right contact of relay 467, brush 404 and its associated contact to Aground through the right inner contact of relay 468. A circuit is established for relay 463 in position 4 of switch 400 which may be traced. from grounded battery, through the winding oi'said relay, brush 405, ,and its iciatcd contact to ground through the right hand contact of relay 468. The operation ot relay 463 establishes a pulse circuit over the tip and ring conductors which r ely be t. rom ground, through the lett outer con ct of relay 463, left outer contactot relay 457, brush 305 and its associated cont le'lit outer contact of relay 353, tip spring t i jack 392, and thence over the tip conductor of the selector switch (Fig. to the register' apparatus of the sender as previously traced upon the operation of relay 462. Grounded battery is associated with the ring conductor through high resistance 474, lett inner contact of relay 463, resistance 47.3, outer right back contact of relay 457, brush 304 and its associatedcontact, right outer contact of re- (Fig. 2), to the sender register apparatus as previously traced. The operation oit relay 463 further establishes a circuit to operate relay 461 from grounded battery, through its winding, right norn'ial contact of relay 462.

associated contact to ground throul brush 301 and its associated Contact. As previously described the ope-ration of relay 461 operates relay 467 and rotates switch 400 one posi-- `tion from 4to 5 and upon the rotation of the switch, relays 461, and 467 are released. The release or' relay 46'55'edvances switch 400 one position from 5 to 6 in the manner previously described. In this vposition of 'the switch a circuit is established to energize relay 464 troni Vgrounded battery, through its windinhj, brush 405 and its associated contact to ground through the right inner Contact of relay 468. Since the test man actuated key 416, the tip conductor open and therefore no potential is t. 'ed over this conductor to the sender register apparatus through the contacts et relay 464. Ground is' Connected to the ring conductor over a circuit Which may be traced through the lett outer conta-Otel relay 464',

layv 466, resistance 47 3, brush 304 and its associated conta-ct, rieht outer contact o'lrelay 353, 'ring` springoi jach 392 and thence' over the ring conductor of the selector switch (Fig. to the sender r p' "er apparatus. This :is Without ei'lect since t .-.c tip conductor is open. The relay 461 is operatecithrough the right Contact oilrelay 464 in the saine manner as described through the contacts of relays 463 and 462. Switch vviced to 'position 7 through the comu and to position through the con lay 467 upon its release.

in energizing circuit for relay 465 cstahlished in position 8 or switch 400 troni grounded battery, through the 1indi or said relay, brush 405 and its associated con-V tact `to groiunl through une right Vinner contact of relay 468. A ground now connected to the tip conductor, and battery through a low re tance is connected yto the ring conel" the loep elitending to the sender xr zuiparatus for transmitting a heavy negative pulse. The tip circuit may be traced 'troni ground through the lei't outer Contact 'olf relay 465, left outer Contact of relay 457, brush and its associated contact, left outer Contact of relay 353, tip spring ol jack and thence over the tip conductor ot ,fa/lector switch (lli to the send ,r reg;- paratus. i

may h resistance 470, rib 'contact of relay 454. right contact o' key 416ri bt outer contact el: relay 451, left inn xr conv i oi relay 465, resistance 473, right outer Contact oi' relay 457, brush 304 and associated Contact, right outer Contact of relay 353, rinogspring of jack 312, and thence over the ring conductor of the selector' switch 2\ to the sender register apparatus. rlhe operation of reluyl465 further establishes an energ1V i' u circuit for relay 461 which in turn establishes an energizing` circuit 'for relay 467 in the manner previously descrihed. 'lhe switch 400 progresses from position 8 to position 9 lett outer Contact of re-V `ic Winding; et lowv under the control orf the circuit established through the contact of relay 461 and iii/"om position 9 Vto position 101over the circuit established through the normal Contact of relay V 467 upon its rel-ease.A ln this position a eircuit is stablished to operate relays 450 andA 451 from grounded battery in series through their windings 4brush 405 and its associated Contact to ground through theright inner Contact of relay 468. 'The' operationof relays 450 and 451 transfers the pulsecontrol. leads froml the thousands keys 410 to 419in elusive to the tens keys`420 to 429 inclusive.,

The operation of relay 451 further establishes a circuit to rotate switch 400 from lposition 10 to position 12. This circuit may be l traced from grounded battery, through the Winding and associated Contact of switch magnet 407, right inner contact of relay 451,V brush 404 and its associated contacts in positions 10 and to ground through the right Y innercontact of relay 4.6-8.- l y A circuit is again established lor relay 462 l in positi a 12 from grounded battery, through 4its Winding, right inner Contact of relay 457, brush 405 andA its associated contact to groiind, through the right rinner Contact of relay 468. The first tens pulse is transmitted to the sender through the contacts of this relav. y y f It Will` be remembered that tens ke 424 is the one operated by the test man. he tip conductor is opened at key 424 zand thus no potential is impressed over this conductor through the contacts of relay 462. A ground is connected vto the rin-g conductorthrough 304 yand its associated Contact, outer Contact of relay 353, ring 4.conductor ofja'ck 392 and thenceover the rin-g conductor of the selector to the register apparatus ofthe sender but is Without ellect since the sender loop is open at the tip conductor. The operation oi? relay 462 further establishes' an operating circuit for relay 461 and the operation of `relay 461 establishes. an :energizing circuit for relay 467, Switch 400 `is .nowladvanced into position 14 inthe manner previously de@ scribed for the .advance of this switch.

Relay i462 Vis released and an energizing circuit is established for relay 463 in position14 ofthe switch Jfrom,grounded battery, through its Winding. brush .405 and its associated Contact to ground throuo'h the right inner contact Vof relay 468. `The operation of relay 463 vconnects ground with the tip conductor over a circuit traced through the left outer contact offrfl'ay 463, left-outer contact of relay 457 brush v'305 `,and t'sassociated contact, left outer contact of relay 353, tip conductor of jack' 392 andt'henc'e over the tip conductor of the selector, Fig. 2, to the senderl register apparatus. Battery ,v is connected through a highresistance With the rngconrau ductor over a circuit which may be traced from grounded battery, through resistance 474, left inner contact of relay 463, resistance 473, brush 304 and its associated contact, right outer contact of relay 353, ring conductor of jack 392 and thence to the sender reg-v ister apparatus as previously traced. r1`he resulting impulse over the sender loop is weak and of negative polarity. The operation of relay 463 further establishes an energizing circuit for relay'461 and in turn for relay 467 to rotate the switch 400 into position 16 as previously described.

Relay 463 is released and an energizing circuit is established for relay 464 from grounded battery, through its winding, brush 405 and its associated contact to ground through the right inner contact of relay 468. The operation of relay 464 associates battery through a high resistance with the tip conductor over a circuit which may be traced `from grounded battery, through resistance 471, right inner contact of relay 454,1eft conact of key 424, left outer contact` of relay 453, left contact of relay 451, lett inner con#- tact of relay 464, leftinner contact of relay 466, left outer contact of relay 457, brush 305 and its associated contact, left outer contact of relay 353 tip conductor of jack-392 and thence to the sender register apparatus as previously traced.` Ground is associated with the ring conductor through the left outer contact of relay 464, left outer contact of relay 466, resistance 473, right outer contact of relay 457, brush 304 and its associated contact, right outer contact of relay 353, ring spring of jack 392 and thence to the sender register apparatus as previously described.. The resulting limpulse-'over the sender loop is positive. The operation of relay 464 further establishes an energizing circuit for relay 461 and the operation of relay 461 establishes an energizing circuit for relay 467. Switch 400 is now rotated to position 18 in the manner previously described.

Relay 464 released and an energizing circuit for relay 465 is established Afrom grounded battery through its winding, brush 405 and its associated contact to ground through the right inner contact of relay 468. The operation of relay 465 associates a ground potential with the tip conductor through the left outer contact of relay 465, left outer contact of rela 457, brush 304 and its associated contact, left outer contact 'of relay 353, tip spring of jack 392 and thence to the sender register apparatus as previously described. Battery potential is associated through a highrresistance 475 with the ring conductor throughthe left inner contact of relay 465, resistance 473, right .outer contact of relay 457, brush 304 and its associated contact, right outer kContact of relay 353, ring spring ot jack 392V and thence to the sender register apparatus as previouslydescribed. The resulting impulse is weak and of negative potential. The operation of relay 465 further establishes a cirtact to ground through the right inner conv tact of relay 468. The operation of `relays 452 and 453 transfers the pulse relays from the tens key set to the units key set. The operation of relay 453 further establishes a circuit to rotate switch brushes 401, 402 and 403 to terminal 1. This circuit may be traced from grounded battery, through the winding and associated contact of magnet 407, right inner contact of relay 453, brush 404 and its associated contacts in positions 20, 21 and 22 to ground through the right front contactof relay 468.

Switch brushes 401, 402. and 403 are now associated with the terminals of position No. 1 and brushes 404, 405 and 406 are open. A circuit is now established to rotate switch 400 from position 1 to position 2 where the pulsing` apparatus is again associated with the tip and ring conductors extending to the sender. The circuit for rotating switch 400 may be traced from grounded battery, through the winding and associated contact of magnet 407, right normal contact of relay 467, brush 401 and its associated contact to ground through brush 301 and its associated contact.

An energizing circuit for relay 462 is established in position 2 of switch 400. This circuit Inay be traced ironi grounded battery, through the winding of relay 462, right inner contact oi relay 457, brush 402 and its associatod contact, to ground through the right inner contact oi' relay 468. Battery is now connected through high resistance 471 with the tip conductor through the right inner Contact of relay 454, lett contact oi key 433, lett contact of relay 452, left contact of relay 450, left inner contact of relay 462, left inner Contact ol" relay 466, lett outer' Contact of relay 457brush 305 and its associated Contact, left outer contact ot relay 353, tip spring oi ack 392 and thence to the sender register apparatus as previously traced. A ground is associated with the ringconductor through the left outer contact ot' relay 462, left outer contact of relay 466, resistance 47 3, right outer contact of relay 457, brush 304 and its associated. contact, right outer contact of relay 353, ring spring of jack 392 thence to the sender l register apparatus. The resulting pulse ofcurrent over the sender loop is ott positive polarity. The operation oft relayf462 further establishes an energizing circuit for relay 461 which may be traced from groundod battery, through its winding, right Contact :of relay 462, brush 403 and its associated contact to ground through brushBOl and its associated Contact. The operation otrelay 461 establishes an energizing circuit lor relay v467 and an energizing circuit for switch magnet 407Vv to rotate the switch lroui poi tion V2 to osition 3. The energizing` circuit 'for inaff- ZL in, PJ

net 407inay be traced from grounded battery,

through its winding and associated contact, left contact oit relay 461, brush 401 and its associated `Contact to ground through brush 301 and its associated Contact.. Uponft-he-rotationv oil4 switch 400 frein position 2 toposiftion 3- the energizing' circuit for relay 461 is opened to cause its release, husopening the energizing circuitior relay 467 which-slowly releases.V The rotation oit switch 466frorn position 2 to position 3 inn-ther opens the energizing circuittor relay 462 to cause its release. lThe release of relay 46T establishes an energizing circuit'tor switch magnet 40'7- to rotate t-he .switch frein position. 3 to position 4. This energizing circuit inay be traced 'lll . described.

from grounded battery, through lthe winding and associated Contact of niagnet40'?, right normal Contact of relay 467, brush 401 and its associated contactv to ground through the brush 301 and its associated contact A circuit is now established to operaterelay 463 'from groundedy battery, through its winding, brush 402 and. its associated con- ,tact'to ground through the inner right contact ot relay 468. The operation oit relay 463 associates ground potential with thetip conductor through the left outer contact of relay 463, lett outer contact of rela-y 457, brush 30V and its associated contactri, ht oiijter contact of relay 853, tip spring ot jack 292 and thence to the sender register apparatus as previously Battery potential through low resistance 470 is associated with the ringconductor through the right outer norinal contactof relay 454, right contact of key 433, right outer contact. of relay 452. right outer "Contact ot' relay 450, lett inner contact ot relay 463, resistance-473, right outer Contact ot relay 457, brush 304 and its associated.

cont-act. right outer Contact oit' relay 353, ring' `j spring ot jack 392 and-'thence to the senderV register apparatus as previousy described.

Jl-.n impulse ot heavy negativepotential 'is thus tansinitted over the/loop extending to the sender. The operation oit' relay 463 'urther establishes an energizing circuit 'for re-V lay 461 and the operation ot rela-y 461- establishes .an energizing circuit :for relay 46?.; The operation'of relay 461 further establishes. an energizing'v circuit for 'nii-ignoti. 407 to rotate t-he switch 4.00 troni` position 4 V'to position 5 in the manner previously describiul.

In position 5 the energizing circuit for relays 461 and 463 is opened to cause their release. The release of relay 461 opensthe energizing circuit for relay 467 to cause its release which establishes an energizing Acirc-uit for magnet 407 to rotate switch 460 troni position 5 to position 6. f

In this position ot the switch a 'circuit is established to operate relay 464 trein grounded battery, through its Winding, brush 462 and its associated contactto ground through the right inner contact ofi-clay 466. The operation ol' relay 464 does not close 'the tip conductor, but associates a groundpotential with the ring conductor through thc lett outer ooiitact ot' relay 4.64, lett outer norinal vcontact oi relaiT 466, resistance 4?'3right under contact ot relay 467, brush 304 and its associated contact, right outer contact oit Vrelay 353, ring spring'of ack Zzl92'and thencejto the sender registerapparatus as previously described. Since the tip conductor. is open no iinpulseris sent over thc loop-,tor the sender.

The operation'ot relay 464 establishes an energizing circuit `for relay 46l'and the operation et relay 461 establishes an energizing circuit tor relay 467 to rotate switchl 40() 'troni position 6 teposition 8 in the manner previously described. Relay 464 isreleased Vupon the rotation oit the switch.` and an energizing circuit is established tor relay 465V when the switchbrush 402 Varrives in position 8. l f i Ground is now associated with the'tipconductor through the lett outer contact ot rei ir .i ray 46o, leit outer norinal contact. oi .relay 45?, brush 305 and its. associated con tact, lett outer contact ot relay oat-l. tip spring` ot' ack 392 and thence to the sender registerapparatus. vllattery through high resistance 475 is associated `with thering conductor through the left inner contact of relay 466, resistance' 473, right outer contact of'relay 4o?, brush 364 and itsV associated. contact, right outer contact of relay 353, ring spring oif, jack-'392 to the senderregister apparatus.V rlhe re-y sultant .iinpu-lse is therefore weak and'oi Yneg'- atiye potential. The operation ot relay may be transmitted to the senderwhich represent zero pulses. Suilicientpulses .haare already n been transmitted to the sender. Vto

position. the code registers tor directing fact of relay 468.'r 'llheoperation ot ren and-466v arranges the pulsingV circuit in such la ina-nner that a series of .pulses y ill) the selector switch, Fig. 2, to the test line. It is, however, necessary to transmit a series of ten light negative pulses to the sender in order to satisfy the sender numerical and station registers. The light negative pulses in the order transmitted are known as zero pulses.

The operation of relay 466 establishes a circuit to advance switch 400 from position 10 to position l2 trom grounded battery, through the winding and associated contact ot' switch magnet 407, right outer contact of relay 466, brush 401 and its associated contacts in positions 10 and 11 to ground through brush 301 and its associated contact in position 15. An energizing circuit is established for relay 462 in position 12 of switch 400 from grounded battery, through the Winding of said relay, right inner' Contact oi relay 457, brush 402 and its associated contact to ground through the right inner contact ot relay 468. Ground potential is now associated with the tip conductor through the left outer contact of relay 462, left inner contact of relay 466, lett outer `contact of relay 457 and thence to the tip conductor of the selector switch, Fig. 2, and the sender register as previously traced. Battery potential is associated with the ring conductor through high resistance 471, right inner Contact of relay 454, left inner contact of relay 462, left outer contact ot relay 466, resistance 473, right outer contact of relay 457l and thence to the ring conductor of the selector switch, Fig. 2, and sender register apparat-us as previously described. This represents the irst of a series of zero pulses transmitted to the sender. The operation of relay 462 further establishes an energizing circuit for relay 461 Which in turn establishes an energizing circuit for relay 467 in the manner previously described to rotate switch 400 from positionl 12 to position 14. Relay 462 is released and an energizing circuit is established for relay 463 in the lnanner previously described. The operation of relay 463 associetes ground `potential with the` tip conductor through its left outer contact, the lett outer contact of relay 457 to the tip conductor of selector switch, Fig. 2, and sender register as previously described. Battery is associated With the ring conductor through high resistance 474, leilt inner contact of relay 463, resistance 473, right outer contact of relay 457 to the ring conduct-or ofthe selector,

Fig. 2.` and sender register as previously described. A second impulse of light negative potential is therefore transmitted overthe sender loop circuit. The operation ot relay 463 further establishes energizing circuits for relays 461 and 467 as previously described to advance the switch 400-fron1 position 14 to position 16. Relay 463 is released and an operating circuit is established for..relay 464. The operation of relay 464 again associates ground potential With. the tip conductor through its left outer contact, lett inner contact ot relay 466, left outer contact ot rehiy 457 to the tip conductor oit the selector, Fig. 2, and sender registers. Battery potential is associated With the ring conductor through high resistance 471, lett outer contact oit relay 454, left inner contact of relay 464, lett outer 'contact of relay 466, resistance 473, right outer contact ot relay 457 and thence to the ring conductor of the selector, Fig. 2, and sender register apparatus, resulting in the transmission of a third impulse oit light negative potential. The operation ot relay 464 tui-ther establishes a circuit to operate relay 461 which in turn establishes a circuit to opcrate relay 467 which combination advances switch 400 from position 16 to position 16. Ylelay 464 is releaL ld upon the rotation ot switch 400 out of position 16 and a circuit tor relay 465 is established in position 18. The operation et relay 465 again associates ground. potential With the tip conductor through its lett outer contact and the left outer contact ot relay 457. Battery potential through high resistance 475 is associated with the ring conductor through the lett inner contact ot rclay 465, resistance 473, right outer contact oi" relay 457 and thence to the sender register apparatus as previously described. This re sult-s in the transmission oit a fourth impulse ot light negative potential. The operation ol relay 465 further establishes an energizing circuit for relay 461, the operation ot Which establishes a circuit for relay 467 to advance switch 400 from terminal 18 to terminal 20 in the manner previously described. Upon reaching terminal 20 a further circuit is es tablished to energize switch magnet 407 to rotate the switch to position 1. This circuit may be traced .trom grounded battery, through the Winding and associated contact ot magnet 407, brush 401 and its associated contacts in positions 20, 2l and 22 to ground through brush A301 and its associated contact. It will be noted that when brushes 401` 402 and 403 have rot-ated beyond terminal 22, brushes 404, 405 and 406 are resting upon terminal 1 and therefore circuits are established through these brushes for further operation ot the pulse relays to complete the zero pulses to be transmitted to the sender register apparatus. Four zero pulses have been transi mitted out oit a total ton which are required to satisy the sender. Switch 400 is advanced Ytrom position l to position 2 since a circuit is established to energize magnet 407 upon its arrival in position 1. This may he traced from grounded batteryv throufgjh the wi "d ing and associated contact oit' magnet left Contact ot relay 459, right oiiter contact et c relay 460, brush 404 and its associated contact to ground through the right inner con y tact of relay 468.

sin energizing circuit tablished In position el" :witch 4( Vnot 407 frein grounded battrroundcd battery tl'nfougi'h its Winding, right 57, brush 405 and its o nd, thro ugh the ation relay 462 associates a ground With,

the tip conductor and battery With `the ring; conductor through high resistance 47l for transmitting' a Zero pulse to the sender apparatus. Si.' tch 400 is rotated to position 4 by the operation et relays 461 and 467. Relay 482 is released and relay 468 oper g i the manner p 'icusly described. A y is now associated with the tip and battery through a high res' inee l associated With the rin gg the same reyiously described and the switch 400 is r.,.,atcd to position 6. ln position 6, ri' ay `464 operated transmit the sere-nth pulse d in Ygjos'ition 8, relay 465 'is operated to transmit the eighth sere pulse to the sender ap atus tion ot relay L65 cau switch 400 tov rotate from poi. onv8 to posi V.on l() by operating' relays 46l and 46T. ln position 1G, a circuit is immediately established to rotate switch 400 to position l2 by the'enei 'ization ot' niagthrough its 'winding and associated contact, right inner Acontact ot relay 451, brush 404 and its associated contact to ground through the right inner contact of relay 468. ln position l2, a circuit is established to operate relay 462 to transmit the ninth Vnero pulse to Vthe sender register apparatus and to rotate the switch into position 14. ln position 14, relay 463 is operated to transmit the tenth Zero pulse to the sender register apparatus. The operation ot relay463'again operates relay 461 to The operarotate switch 400 into position l5 asA previously described. A circuit is now established to operate relay 468 'troni grounded battery through resistance 479, Winding` of relay 468, riwht inner Contact ot relay 466, brush 406 and its associate l contact to cjround through brush 801 and s assozizted contact. Relay 468 locks through its left coi'itact and estab lishes a circuit through its right inner consi tch now rotates,under the control or' its selt-iuterrupting Contact, one cor'iplete revolution aiuluntil brush 408 is associated `,with the Contact in position i9 Where a shunt cir* cuit is established to release relay 468. This shunt circuit may be traced troni a iioint lietween resistanced) d the Winding' ot relay 468 throuf i brush 408 an d its associated contact to M mnd through bi ish and its ociated contact. The operation ot' relay 468 further opens the locking); circuit 'for rclays 450. 451, 452 and 453 to cause their release. Upon the release of relay 468, magnet 40T releases and switch 400 progresses to position No.20. circuit .is estal'ilished to energize sy-Jitch inagnet 40'? in order that switch 466 may be rotated to normal. This circuit inay betraced The f sition 4, the circuit for relay 368 is ln positions 20, 2l and 22, a

from grounded vbattery througfrh the Winding,l and associated Contact ot magnet 40?', brush 401 and its associated contacts in position 20, 2l and 22 to` ground through brush and its associated contact.

During; the operation et relay 468, circuit was established to rotate switch 300 troni position l5 to position 16. rllhis circuit inay be traced ir in grounded battery through the Windinf` and associated contact et 807,1if 1 outer contact ot relay 438 i through brush 308 and its associated in position Lamp 4. upon the advance oit switch SOO.

Upon the completion ot pulses transmitted 'lrorn the testing` 'circuit to t e sende register apparatus, the selector switch (Fig. il) is brought under the control ot' said sender and D Y ound contact Yguished the selector sequence switch rotates into position 4. A circuit is thus established to energize relay 368. This inay be traced'troin grounded battery through the winding' oiV foo 392, iight outer Contact ot relay 353, brush Y v804 and its associatedl contact, Winding oi 'relay'368, brush S05-and its associated contact, lett outer contactof relay353, tipspring ot jack 882, tip of plug 254, patching cord 250 and plugl 228, tipV spring ot jaclr 229, con

yductor 252 to ground through the right contacts of cani 2li. Relays 223 Yand 268 operate in the circuittrace'd. The operation of relay 223 energizes relay222 to establish circuitsy for the advancement 'of the selector sequence switch as described in the patent to `VV1llia-.fn

vL. Dodge hereinbetore mentioned. The operation ot' relay 368 establishes a circuit to I operate relay 360 lroni grounded battery through the Winding or" saidrelay, right nor Inal Contact ot relayf'l, left lower contact of key 342, contact of relay 868 to ground through the left upper contact ot key 842. The operation ot' relay 86() extinguishes lamp 338 and lights larnp 339 troni grounded battery through its lilament, ri ght outer contact oft relay 360, brush 306 and its associated contactto ground through the lower Contact ot key480.y The operation ot relay 860 further establishes a circuit to yenergize switch inagf net 307 from grounded battery throivrh its Winding, lett 'inner contact ot relay o6@ to ground through brush 803 and its associated contact. The selector sequence switch continues to rotate under thecontrol ot the cir. cuit established and upon rotatir opened to cause its release. The release ot' relay 868 opens'the energizing circuit for ii'elay 360 to cause its release. and the release oft-relay opens the energizing circuit for magnet 307 to propell the brush assembly troni posit-ion 16 to position 17. Lamp '841 is new lighted to indicate to the test inan that the selector seout olf poquence switch has progressed beyond position 4. This circuit may be traced from grounded battery through the lamp filament, right inner contact oi' relay 360, lett outer normal contact of relay 367, brush 306 and its associated contact to ground through the lower contact of key 480.

When the district selector sequence switch has rotated to position 5, a. circuit is again established to operate relay 368 which circuit is the same as previously traced for its operation `with the exception that grounded battery through the winding of relay 223 is carried to the left upper and right lower contacts ot cam 211 and thence over the tip conductor instead of over the ring conductor as previously traced. Also, ground is associated with the ring conductor through the left contacts of cam 215 and left upper contact of cam 216. The operation ot' relay 368 establishes the circuit previously traced to operate relay 360. Lamp 341 is extinguished and lamp 340 is lighted from grounded battery through its filament, contact of relay 360, lett outer normal contact of relay 367, brush 306 and its associated contact in position 17 to ground through the lower contact of key 480. Upon further movement of the district selector sequence switch (Fig. 2) the energizing circuit for relay 368 is opened to cause its release. Relay 360, however', does not release since an energizing circuit through the winding ot relay 367 establishes a locking circuit for relay 360. The release of relay 368 removes a shunt path from the Winding of relay 367. This shunt path may be traced to the ground established by the operation of relay 360. The energizing circuit for relay 367 may be traced from grounded battery through the windings of relays 360 and 367 left outer contact of relay 360 to ground through brush 303 and its associated contact. The district selector (Fig. 2) is now further controlled by the sender to select the test line indicated by terminals 236, 237 and 238.

After the selection of the test line, the district selector sequence switch moves into position 12 for selections beyond. Since there are no further selections to be made, the selector sequence switch magnet is energizedby the sender to rotate the sequence switch to position 13. In this position of the selector sequence switch a bridge circuit is associated with the tip and ring conductors ot the test line to energize relay 361 of the testing circuit. This circuit may beftraced from grounded battery through resistance 378, winding of relay 361, right normal contact of relay 362, tip spring of jack 316, tip oi plug 225, patching cord 251 and plug 226, tip spring oit jack 227, terminal 238, brush 235, right lower contact of cam 208, outer lei't contact of relay 222, lett upper contact oit cam 213, brush 234, terminal 237, ring spring of ack 227, ring of plug 226, patchingcord 251 and plug 225, ring spring of jack 316, to ground through thevvuppermost contact ot key 344; The operation ot relay 361 establishesan obvious energizing circuit for relay 363, relay 363 l cking over the circuit previously traced to the selector of Fig. 2. The operation oi relay 363 establishes an obvious energizing circuit for relay 362. The operation ot relay 362 opens the energizing circuit i'or relay 361 to cause its release. The operation oit relay 362 further establishes a circuit to light lamp 334 as an indication to the test man that the district selector 2) is properly iunctioning The lamp circuit may be traced it'rom grounded battery through resistance 379, filament of lamp 334, left contact of relay 362, lower contact of key 348, left outer contact oi' relay 367, brush 306 and its associated contact, to ground through the lower contact ot key 480. T he district selector sequence switch continues to rotate through positions 13, 14 and 15 and upon its rotation beyond position 151,42 the bridge holding circuit orrelay 363 is opened and a locking circuit is substituted in the form ot' a continuity test ot' the talking couductors and apparatus associated therewith in the selector switch circuit Fig. 2. In position 16 of the district selector sequence switch a circuit is established from the testing circuit to the test line over the tip and ring conductors of the district selector (Fig. 2) and thence over conductors 252 and again to the testing circuit. VThis may bc traced from grounded battery through the winding and right contact oi' relay 363, tip spring of jack 316, tip ot plug 225, patching cord 251, plug 226, tip spring ot jack 227, tip terminal 238, brush 235,1eft upper contact of cam 214, conductor 252, tip spring ot `jack 229, tip of plug 228, patching cord 250 and plug 224, tip spring ot jack 392, lett outer contact of relay 353, brush 305 and its associated contact, winding olf relay 368, brush 304 and its associated contacts, right outer contact ot relay 353, ring spring of jack 392, ring ot plug 224, patching cord 250 and plug 228, ring spring of jack 229, conductor 253, right upper contact of caln 213, brush 234, terminal 237, ring spring ot jack 227, ring of plug 226, patching cord 251 and plug 225, ring spring of jack 316 to ground through the uppermost contact ot key 344. It' the continuity circuit is established as traced, relay 363 remains locked and relay 368 operates. The operation of relay 368 establishes a circuit to light lamp 337, and to operate relay 456 from grounded battery through the winding oi' relay 456, filament of lamp 337 right contact of relay 367, left lower contact of key 342, contact of relay 368 to ground through the left upper contact of key 342. The operation ol? relay 456 is not eiiective this time. The lighting of lamp 337 and lamp 335 indicates to the test man that the district selector has rotated its sequence switch into talkingposition that it has propL erly responded to the setting of the sender y registers in response to the pull es transmitted thereto. f

The test oit the local district selector circuit is'now completed and key S315, is operated to rotateswitch. 300 to normal over a circuit which may be traced irom grounded battery through thewindingl and associated contact oi switch magnet 'f'lyhruslir 302 and its associated contacts to Yground through the ruppermost contact ot ley 345. When switch BOOlras been restored to `normal a circuit is esialelishedto light lamp .333 from grounded battery through thelamp filament, lett inner .normalcontacti otrelay 35'?, brush 806 and its associatedicontaet to ground through 'the lower contacto-ft lkey 480'. The operation et key 345 further opens the holding circuitsfor. relays which are in an operated position at they time that the testis completed.

`What is claimedy is:

l. Inra telephone-exchange system, means iortransmitting trains. of impulses ot `various characteristics7 said means comprisingvli'eys operable to varythec-haracter et impulses in each train',` relays progressively operable to establish -eircuitpaths for the transn'iission of theindividual impulses of Ieach train and a stepehystep switch-to control the progres sive .opera-tion4 of said relays.

2. In a telephone'exchange system, means for transmitting :trains ofrimpulses, said impulsesvary-ing in polarityandi strengthv7 said4 nieanscomprising keys operable to ivary the character of individual impulses of said train, relays progressively operableto establish circuit pathsfor' the-transmissionof the. individua-l'impulses of each train and astep-` hyl-step ,switchto control the progressiveoperationl of said relays.

3. In a telephone exchange system, means Jfor transmitting:trains of impulses of various characteristics, sai-dl `means, comprising keysoperable to vary the character of impulsesin each train, Arelays .progressively operablel toy establish circuit paths forfthe transmission ofthe individual impulses. of each train'y-a step-hystep `switch to control the progressive operation of said relays andmeans underthe controlfvotA said relays to `advance said` switch. Y

4.. In a telephone exchange systennadevi'ee for transmitting'trains oi impulses-ot various characteristics,` comprising a switchhaving stationary contacts and a movable brush,- sai d brush beingwprogressively positioned under the control of the electrical condition-on sue cessive contacts-for Atransmitting trai-nx ot impulses of various characteristics, and

means torvarying the characteristic oftheV rsaid brush being progressively positioned Vunder-the control of the electrical condition on successive contacts 'for varying the'characteristic oi successive f impulses in each train. and meanstor varying the polarity and strength of impulsesitransmitted'in any given position of said' switch.

6. In a telephone exchange system/4 a device y for transmitting trains et impulses of various characteristics,comprising a switch having stationary contacts and amovable brush, said brush hei/ng: progressively positioned under the control oit theelectricalcondition on successive contacts `for varyingthe characteristic otthe successive impulseslin a train-,means for controlling the charac-teristic-l oi the im-v pulse transmitted in any givenpositioncf` said? switch,V and means yoperalole in response to the; :electrica-l3 *condi-tion l of 1 lsaid switch contacts for transmitting thempulses et saidV trains.

7. In a l telephone exchange system,` a device ttortransmittingtrains of Vii pulsesoi various characteristics, A'comprising `switch havingr stationary- :contacts and ai movable' brush, saidk brush lbeing, progressively positioned under tl'iecontrol of the electrical condition on successi-ve contacts-tor varying the characteristicv not success-ive impulses in fa train, means fior varying theA characteristic of the impulse transmitted in .any-givenpositionof said' switch, and relays wirirahly oper-y able in response. to kthe electrical 'condi-tion of said switch contacts'ior transmitting the impulses of -s'aifd trains.' 1;

8. In a tele-phone:exchangegsystem. de.-V vice i'or transmitting trains l'of impulses-oi" various'characteristics compris-ing a switch having stationary contacts and a movable brush7 saidfhruslrheing grogressively positioned uncle-r the control ofthe electrical condition on successive contacts tor varying the characteristic ot successivel impulses v'in a train, keys for varying the characteristic ot the 'im-pulse' transmitted in any ygiven position of said switchyandrelaysvariahly oper- Vahle inresponse to the electrical condition on said switch contacts for transmittingthe impulses of said trains. f

Inwitness whereof,v I hereunto Ysubscribe my name this 23d day et OctohergA. 13-1924.

' ERIC VR. LUNDI-US. 

